1. Field of the Invention
The present invention relates to an apparatus tot in-line thermally treating metallurgic semi-finished products having extended elongated shape, such as bars, rods, wire rods or other semi-finished products having extended elongated shape.
2. State of the Art
In the technical scope of in-line processes for the production of metallurgic semi-finished products having extended elongated shape, it is known the use of thermal treatment apparatuses, in particular for cooling the semi-finished products, typically arranged downstream of a step of machining by plastic deformation, e.g. rolling. Such apparatuses allow to subject the semi-finished products to a controlled thermal cooling treatment or, more in general to a thermal treatment with a predetermined temperature profile or not directly on the production line, so that the obtained product is immediately marketable at the end of the treatment.
Apparatuses are used for this purpose comprising one or more treatment lines including a plurality of treatment units, aligned and coaxial to one another, provided with a respective through cavity, through which the semi-finished product e.g. a bar, to be treated is passed. In particular, applications are provided in which the apparatus comprises a coding circuit connectable to the through cavities to send a cooling fluid to the semi-finished product, performing a thermal cooling treatment thereon when the semi-finished product passes through the cavities. In this case, the treatment units are also known as coolers.
Typically, the treatment units must be replaced according to the size of the bar to be treated. In order to reduce replacement downtime, during which the line is not operational, and thus to increase productivity, such replacements must occur as quickly as possible, or in all cases in a time compatible with the times required for changing the working cylinders in the rolling mill upstream of the treatment apparatus.
The manual replacement method, characterized by long execution times, is a known treatment unit replacement method. Alternatively, there are automatic or semi-automatic devices with low need of intervention by an operator which allow to save replacement times with respect to entirely manual replacement.
Translating carriage apparatuses on rail are known among the latter. A plurality of cooling units aligned along a direction parallel to the rails are provided an such apparatuses. By translating along the rails, each cooling unit may be taken to operating position so as to be aligned with the direction of advancement of the semi-finished product to be treated.
Such a solution determines a plurality of drawbacks, the main of which are excessive dimensions, poor alignment normally obtainable between cooling units and difficult access to the cooling units due to the linear development of the device.
In order to avoid such drawbacks, a rotating drum apparatus has been developed, being provided with a plurality of cooling lines regularly arranged at constant angular distances along the perimeter region of such a drum. By rotating the dram about its rotation axis, each cooling line may be taken to the operating position so as to align it with the direction of advancement of the bar to be treated. Each cooling line comprises a plurality of cooling units aligned and coaxial to each other, through, which the bar to be treated is susceptible of passing when the cooling line is placed in operating position. However, such an apparatus, described in detail in document EP0317785, is not an optimal solution because it also displays a series of drawbacks.
One drawback is the fact that the rotation axis must also be moveable with respect to the outer casing in which the drum is accommodated in order to guarantee the correct coupling between the cooling circuit and each cooling line when the latter is arranged in operating position. This determines both constructive complications and, once again, a non-optimal, and in all cases improvable, alignment. Furthermore, the cooling units described to EP 0317785 are improvable with regards to maintenance mid cleaning operations, e.g. cleaning of the scale which deposits on the inner walls of the cooling units, and to remove cobbling.
In order to facilitate such maintenance, cleaning and cobbling removal operations, an opening cooling unit has been created, as the one described in U.S. Pat. No. 5,257,511. However, the device in U.S. Pat. No. 5,257,511 does not solve in all the aspects the other products described above. Indeed, in all conditions other than maintenance and cleaning, the covers of the cooling units must be blocked in closed position. The handwheel closing system described in U.S. Pat. No. 5,257,511 although effective with this regard, in all cases determines the need for a manual intervention by the operator, with consequent increase of the time during which the line must remain inactive.